“They are targeting the innocents,” he said. “People have become too scared to get treatment at hospitals, as they have become the targets.”

Local Coordination Committees, an activist group that monitors the Syrian civil war, said 50 people were killed and over 100 were wounded.

Civil defense members try to rescue victims from the wreckage of National Hospital after a Russian air strike in IdlibCredit:
Mohammad Amen Qurabi/Anadolu Agency/Getty

The UK-based Syrian Observatory for Human Rights said that the strikes appeared to have been carried out by Russian aircraft.

"The air strikes are the most intensive on Idlib since the beginning of the truce," said Rami Abdel Rahman, the organisation’s director.

Members of the Syrian Arab Red Crescent help a wounded victim into an ambulanceCredit:
OMAR HAJ KADOUR/AFP/Getty

"Even though Idlib is not covered by the ceasefire, it had been relatively calm with only intermittent raids," he added.

Idlib is largely controlled by rebel groups, including al-Qaeda-linked Jabhat al-Nusra. However, they do not have the popular support of many of the people they govern, with residents holding regular protests against their rule.

Nusra is not party to a Russian- and US-brokered ceasefire that came into force on February 27 between Moscow-backed government forces and Washington-backed non-jihadist rebels.

The scene in a hospital in Idlib following Russian air strikesCredit:
OMAR HAJ KADOUR/AFP/Getty

Russia has been criticised by the US-led coalition for targeting moderate rebels they are supporting, and not just terrorist groups Islamic State and Nusra.

The Russian ministry of defence denied responsibility for the air strikes, as it does with most attacks which hit civilian areas.

According to Observatory figures, Russian air strikes have killed more than 2,000 civilians, including 500 children and 300 women, since Moscow began its aerial campaign in support of President Bashar al-Assad last September.

The wave of violence came a day after the opposition’s chief negotiator quit the Geneva peace talks, throwing them into serious doubt.

Civil defence members try to rescue victims from the wreckage of National Hospital in IdlibCredit:
Mohammad Amen Qurabi/Anadolu Agency/Getty

Mohammed Alloush blamed the international community for not being “serious” about finding a solution to the five-year conflict and for standing back as Syrian government forces continue attacking the opposition and besieging rebel-held areas.

The last round of talks was held in April and no date has been set for the next.

The death toll of the civil war has risen to more than 400,000 people while half the country's population have been forced from their homes.